Examination of temporal controls at the level of transcription. With the availability or purified nuclei, characterization of the polymerases of yeast nuclei and our expertise in RNA sequencing, we will directly test the possibility that nucleoproteins isolated at different stages of the cell cycle have varying template specificities for transcription. Changes in the nuclear polymerases will be investigated during sporulation of yeast. Further tests of the RNA species formed during vegetative growth and sporulation will be undertaken. With the use of the zonal rotor method for analysis of the cell cycle, a number of important problems are now available for investigation. These include mitochondrial biogenesis, mitochondrial and nuclear DNA relationships and the timing of synthesis of specific transfer RNA species. Further characterization of the gamma band of DNA will be undertaken with a particular interest into locating the chronosomes carrying the rRNA genes.